Low-Dimensional Network Formation in Molten Sodium Carbonate.
Low-Dimensional Network Formation in Molten Sodium Carbonate.
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DOI：
10.1038/srep24415
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发表时间：
2016-04-15
影响因子：
4.6
通讯作者：
Skinner L
中科院分区：
文献类型：
--
作者：
Wilding MC;Wilson M;Alderman OL;Benmore C;Weber JK;Parise JB;Tamalonis A;Skinner L
熔融碳酸盐是一种高度无粘的液体，其特点是熔点低，稀土元素和挥发性分子的溶解度高。到目前为止，人们对这些耐人寻味的液体的结构和相关性质的了解还很有限。我们报道了熔融碳酸钠(Na2CO3)的研究结果，它结合了高能X射线衍射、无容器技术和计算机模拟来提供对液体结构的洞察。在空气动力学悬浮炉中，收集了悬浮在不同组成流动气体中的激光加热碳酸盐球的总结构因子(Fx(Q))。通过将碳酸盐阴离子作为柔性实体进行分子动力学模拟，得到了部分结构因子对Fx(Q)的贡献。碳酸盐液体结构与温度密切相关。在低温下形成低维碳酸盐链网络，例如在T = 1100 K时，约55%的C原子形成链的一部分。平均链长随着温度的升高而减小，随着链长的缩短，碳酸盐阴离子的旋转速度加快，促进了Na+离子的扩散。
Molten carbonates are highly inviscid liquids characterized by low melting points and high solubility of rare earth elements and volatile molecules. An understanding of the structure and related properties of these intriguing liquids has been limited to date. We report the results of a study of molten sodium carbonate (Na2CO3) which combines high energy X-ray diffraction, containerless techniques and computer simulation to provide insight into the liquid structure. Total structure factors (Fx(Q)) are collected on the laser-heated carbonate spheres suspended in flowing gases of varying composition in an aerodynamic levitation furnace. The respective partial structure factor contributions to Fx(Q) are obtained by performing molecular dynamics simulations treating the carbonate anions as flexible entities. The carbonate liquid structure is found to be heavily temperature-dependent. At low temperatures a low-dimensional carbonate chain network forms, at T = 1100 K for example ~55% of the C atoms form part of a chain. The mean chain lengths decrease as temperature is increased and as the chains become shorter the rotation of the carbonate anions becomes more rapid enhancing the diffusion of Na+ ions.